Mara Hvistendahl at ScienceInsiderhas corresponded with the team of virologists in Phnom Penh who are working to identify the illness, and while the diagnosis isn’t certain, they say that they’ve found signs of Enterovirus 71 in cerebrospinal fluid from 15 patients. Enterovirus 71 is one of the causes of hand, foot, and mouth disease, a usually benign childhood infection that causes a rash, vomiting, and other symptoms. The disease is very common and usually clears up in a week or so, and, as with most viral infections, has no cure to speak of.

A small proportion of patients with hand, foot, and mouth disease (not to be confused, incidentally, with foot and mouth disease, a livestock infection) do develop neurological complications that can put them in the hospital and even kill them. But, as Hvistendahl points out, the statistics in the Cambodian outbreak are a little odd. Cambodia is a small country, about 15 million people, and for this many kids to be developing complications and dying of them, a truly large chunk of the population would have to be infected. To put that in perspective, neighboring Vietnam, which had an outbreak of the disease earlier this year, has more than 86 million people and reported only 20 deaths.

Health officials don’t know how many people in Cambodia have the disease, nor do the virologists know whether there’s anything unusual about this strain of Enterovirus 71. It’s on their list to find out, though, as they culture more samples and prepare to sequence the strain’s genome.

I did not know that the bovine “hoof and mouth disease” was also called “foot and mouth disease”. Learn something new every day, I guess.

Pippa

Hi Jim – just out of curiosity, where do you live. The term ‘foot and mouth disease’ is used in the U.K. and english speaking Europe. I had never heard of ‘hoof and mouth’ until I came to Canada!
I have seen many children with hand foot and mouth disease when I did my paediatric placement as a young doc, and not one died. (Nor did the one adult – parent – who caught it.) This must be a very different viral strain to the one we had in Britain in the 1980’s. I understood that the trend is for viruses to become less lethal, (so they don’t kill their host and can infect the next person more efficiently,) not more.
I look forward to hearing more about the findings of this group.

Erin

@Pippa The idea that viruses and other parasites become less lethal as they adapt to a host is common, but it’s a bit more complicated than that. That scenario only happens when killing the host is a fitness disadvantage, which is highly dependent upon the disease vector. For example, mosquito-born diseases want to immobilize their hosts, so that it’s more likely that another mosquito will bite them. Making someone that sick will often kill them, but overall it’s a better strategy. It turns out that mosquito nets change the equation; if immobilized hosts are behind nets and can’t be bitten again, it’s no longer advantageous to make them that sick. Widespread use of mosquito nets actually results in less virulent strains of diseases like malaria.

Toby

I wonder if they were former/current child prostitutes who had HIV/AIDS as well? Maybe this otherwise mild infection is fatal if comorbid with AIDS? Its tragic but Cambodia is one of the countries that has a terrible problem with child prostitution.

Veronique Greenwood

Most of the children were under three years old, so that seems unlikely.

Pippa

I think we would be told if they had AIDs as well! Children under 3 have HIV from their parents so, sadly this is not that unlikely. I now remember that the hand foot and mouth disease that we saw in the UK was not an enterovirus. I guess it’s a bit like common names for plants. The same name can mean something very different.